Difficulty: Easy
Correct Answer: nanosecond
Explanation:
Introduction / Context:
Modern physics and electronics often deal with very small intervals of time when studying high speed events such as switching in digital circuits, light pulses, or nuclear reactions. This question checks whether you can correctly match the size of a time interval, one billionth of a second, with its standard name in the metric system.
Given Data / Assumptions:
Concept / Approach:
The metric system uses prefixes for powers of ten. Common time related prefixes are milli for 10^-3, micro for 10^-6, nano for 10^-9, and pico for 10^-12. The key idea is to memorise these prefixes and associate each one with the corresponding power of ten. Then, when a question states the power, you can directly choose the correct prefix and unit name.
Step-by-Step Solution:
Verification / Alternative check:
If you work the other way round, a nanosecond is one billionth of a second, a microsecond is one millionth of a second, and a millisecond is one thousandth of a second. Only nanosecond fits the description of one billionth of a second.
Why Other Options Are Wrong:
Option A: Microsecond corresponds to 10^-6 second, which is one millionth of a second, not one billionth.
Option C: Millisecond corresponds to 10^-3 second, which is one thousandth of a second.
Option D: Picosecond corresponds to 10^-12 second, which is one trillionth of a second and is even smaller than a nanosecond.
Common Pitfalls:
Students often mix up micro and nano because both represent very small times. Confusing 10^-6 and 10^-9 is a common mistake. Building a simple memory aid for the order milli, micro, nano, pico helps avoid this error. Always relate the prefix back to its power of ten rather than just relying on feeling that a word sounds small.
Final Answer:
The correct unit is the nanosecond.
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